Process for the production of amides

ABSTRACT

The present invention relates to a process for the preparation of compounds of formula (I) wherein R 1  and R 2  are each independently of the other hydrogen or C 1 -C 5 alkyl and R 3  is CF 3  or CF 2 H, by a) reaction of a compound of formula (II) wherein R 1  and R 2  are as defined for formula (I), with at least one reducing agent to form a compound of formula (III) wherein R 1  and R 2  are as defined for formula (I), and b) reaction of that compound with at least one reducing agent to form a compound of formula (IV) wherein R 1  and R 2  are as defined for formula (I), and (c) reaction of that compound with a compound of formula (V) wherein Q is chlorine, fluorine, bromine, iodine, hydroxy or C 1 -C 6 alkoxy and R 3  is as defined for formula (I), to form the compound of formula (I); and to novel intermediates for use in that process.

The present invention relates to a process for the preparation ofpyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amides and also to novelintermediates for use in such a process. The present invention furtherrelates to a novel crystal modification ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,compositions comprising it and to the use thereof in the control offungus infestation in cultivated plants.

Pyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amides, for example3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide, arevaluable fungicides, such as are described, for example, in WO04/035589.

WO 04/035589 describes a process for the preparation ofpyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amides (see Scheme 1):

According to WO 04/035589, a 3-nitro-dehydrobenzene generated, forexample, from 6-nitro-anthralinic acids of formula (A) wherein R² and R³may be, inter alia, hydrogen, is first reacted in a Diels-Alder reactionwith a cyclic 1,4-diene of formula (B) wherein R⁴, R⁵, R⁶ and R⁷ may be,inter alia, hydrogen and Y may be, inter alia, CH((i)—C₃H₇)—, to form a5-nitro-benzonorbornadiene compound of formula (C). Subsequent catalyticreduction under standard conditions (for example, Ra/Ni or Pd/C) in asolvent (for example, methanol) reduces both the nitro group and theendocyclic double bond in the 2,3-position and yields a5-amino-benzonorbornene of formula (D). The 5-amino-benzonorbornene offormula (D) can then be reacted with an acid derivative of formula (E),wherein Het may be, inter alia, a substituted pyrazole ring and Q ischlorine, fluorine, bromine or hydroxy, in a solvent (for example,dichloromethane), to form a pyrazolyl-4-carboxylic acidbenzonorbornen-5-yl-amide of formula (F).

The reaction with compounds of formula (E) wherein Q is chlorine,fluorine or bromine takes place, for example, in the presence of a base(for example, triethylamine).

Compounds of formula (F) can also be obtained by reacting the5-amino-benzonorbornene of formula (D) with an acid derivative offormula (E) wherein Het is as defined above and Q is hydroxy in thepresence of an acid-activating agent (for example,bis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride) in the presence of 2equivalents of base.

In such a synthesis procedure, in the preparation of 9-monosubstitutedpyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amides a plurality ofregioisomers are formed. In the preparation, for example, of thepyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amide of formula (F)wherein R⁴, R⁵, R⁶ and R⁷ are hydrogen and Y is —CH((i)—C₃H₇)—, thefollowing five regioisomers are formed at the stage of the Diels-Alderreaction to form the 5-nitro-benzonorbornadiene compound of formula (C):

In the described preparation process, the 9-monosubstituted regioisomer(IA) is obtained only in a low yield.

The separation of the regioisomers and/or the separation ofstereoisomeric forms may be carried out at the stage of thenitro-benzonorbornadiene compounds of formula (C), of the5-amino-benzonorbornenes of formula (D) or of the pyrazolyl-4-carboxylicacid benzo-norbornen-5-yl-amides of formula (F) and is generallyeffected using customary methods, such as, for example, fractionalcrystallisation, fractional distillation or using chromatographicmethods.

In view of the low yield of the 9-substituted regioisomer, such areaction procedure is not suitable for the preparation, especially on alarge scale, of 9-substituted pyrazolyl-4-carboxylic acidbenzonorbornen-5-yl-amides of formula (F).

The aim of the present invention is therefore to provide a process forthe preparation of 9-monosubstituted pyrazolyl-4-carboxylic acidbenzonorbornen-5-yl-amides that makes it possible for those compounds tobe prepared in an economically advantageous manner in high yields and ingood quality.

The present invention accordingly relates to a process for thepreparation of compounds of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, which comprisesa) reacting a compound of formula II

wherein R₁ and R₂ are as defined for formula I, with at least onereducing agent to form a compound of formula III

wherein R₁ and R₂ are as defined for formula I; and(b) reacting that compound with at least one reducing agent to form acompound of formula IV

wherein R₁ and R₂ are as defined for formula I; and(c) converting that compound into the compound of formula I by reactionwith a compound of formula V

wherein Q is chlorine, fluorine, bromine, iodine, hydroxy or C₁-C₆alkoxyand R₃ is as defined for formula I.

The alkyl groups in the definitions of the substituents may bestraight-chain or branched and are, for example, methyl (CH₃), ethyl(C₂H₅), n-propyl (n-C₃H₇), isopropyl (1-C₃H₇), n-butyl (n-C₄H₉),sec-butyl (sec-C₄H₉), isobutyl (i-C₄H₉), tert-butyl (tert-C₄H₉) andpentyl as well as the branched isomers thereof.

The alkoxy groups in the definitions of the substituents may bestraight-chain or branched and are, for example, methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy,pentyloxy and hexyloxy and also the branched isomers of pentyloxy andhexyloxy.

9-Monosubstituted pyrazolyl-4-carboxylic acid benzonorbornenes offormula I are chiral molecules and can occur in various stereoisomericforms. They are shown as enantiomers of formulae I_(I), I_(II), I_(III),and I_(IV):

wherein R₁, R₂ and R₃ are as defined for formula I. The processaccording to the invention includes the preparation of thosestereoisomeric forms of formulae I_(I), I_(II), I_(II) and I_(IV) andthe preparation of mixtures of those stereoisomeric forms in any ratio.

In the context of the present invention, compounds of formula Ia (syn)

wherein R₁, R₂ and R₃ are as defined for formula I, are understood to becompounds of formula I_(I); compounds of formula I_(I); or a mixture, inany ratio, of compounds of formula I_(I) and compounds of formulaI_(II).

In the context of the present invention, compounds of formula Ia (syn)are understood to be, preferably, a racemic mixture of compounds offormula I_(I) and compounds of formula I_(II).

In the context of the present invention, compounds of formula Ib (anti)

wherein R₁, R₂ and R₃ are as defined for formula I, are understood to becompounds of formula I_(III); compounds of formula I_(IV); or a mixture,in any ratio, of compounds of formula I_(III), and compounds of formulaI_(IV).

In the context of the present invention, compounds of formula Ib (anti)are understood to be, preferably, a racemic mixture of compounds offormula I_(III), and compounds of formula I_(IV).

Compounds of formula IV can occur in various stereoisomeric forms, whichare represented by formulae IV_(I), IV_(II), IV_(III), and IV_(IV):

wherein R₁ and R₂ are as defined for formula I. The process according tothe invention includes the preparation of those stereoisomeric forms offormulae IV_(I), IV_(II), IV_(III) and IV_(IV) and the preparation ofmixtures of those stereoisomeric forms in any ratio.

In the context of the present invention, compounds of formula IVa (syn)

wherein R₁ and R₂ are as defined for formula I, are understood to becompounds of formula IV_(I); compounds of formula IV_(II); or a mixture,in any ratio, of compounds of formula IV, and compounds of formulaIV_(II).

In the context of the present invention, compounds of formula IVa (syn)are understood to be, preferably, a racemic mixture of compounds offormula IV, and compounds of formula IV_(II).

In the context of the present invention, compounds of formula IVb (anti)

wherein R₁ and R₂ are as defined for formula I, are understood to becompounds of formula IV_(III); compounds of formula IV_(IV); or amixture, in any ratio, of compounds of formula IV_(III), and compoundsof formula IV_(IV).

In the context of the present invention, compounds of formula IVb (anti)are understood to be, preferably, a racemic mixture of compounds offormula IV_(III), and compounds of formula IV_(IV).

In the context of the present invention, a “racemic mixture” of twoenantiomers is understood to be a mixture of the two enantiomers in aratio substantially equal to 1:1.

The process according to the invention is suitable especially for thepreparation of compounds of formula I wherein R₁ and R₂ are methyl.

The process according to the invention is suitable very especially forthe preparation of compounds of formula I wherein R₁ and R₂ are methyland R₃ is CF₂H.

In the process according to the invention, preference is given to theuse of compounds of formula II wherein R₁ and R₂ are methyl.

In the process according to the invention, preference is given to theuse of compounds of formula III wherein R₁ and R₂ are methyl.

In the process according to the invention, preference is given to theuse of compounds of formula IV wherein R₁ and R₂ are methyl.

Process Step a):

In one embodiment of the present invention, a single reducing agent isused in Process Step a).

A suitable reducing agent for Process Step a) is, for example, hydrogenin the presence of a metal catalyst.

Suitable amounts of reducing agent for use in Process Step a) in thatembodiment of the invention are, for example, up to 4 equivalents, withpreference being given to 4 equivalents for that reaction.

Process Step a) is preferably carried out in a closed vessel.

In an embodiment of the process according to the invention in whichProcess Step a) is carried out in a closed vessel, an excess of hydrogenis, for example, introduced into the reaction mixture in which the metalcatalyst is already present. The consumption of hydrogen is thenmonitored over the course of the reaction time. In that embodiment ofthe process according to the invention, the reaction is preferablystopped when the desired amount of hydrogen has been consumed.

Suitable metal catalysts are, for example, platinum catalysts, such as,for example, platinum/carbon catalysts or PtO₂; palladium catalysts,such as, for example, Pd/C; rhodium catalysts, such as, for example,Rh/C, Rh/Al₂O₃ or Rh₂O₃; nickel catalysts, such as, for example, Raneynickel; or iridium catalysts, such as, for example, Ir(COD)Py(Pcy); andmixtures thereof. Preference is given to platinum catalysts, palladiumcatalysts, rhodium catalysts or nickel catalysts; special preference isgiven to palladium catalysts, rhodium catalysts or nickel catalysts; andvery special preference is given to Pd/C, Rh/C or Raney nickel.

Suitable amounts of metal catalyst for that reaction are, for example,from 0.001 up to 0.5 equivalent, especially from 0.01 up to 0.1equivalent.

That reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, alcohols, such as methanol,ethanol, propanol or isopropanol, or aprotic solvents, such astetrahydrofuran, tert-butyl methyl ether, dioxane, toluene or ethylacetate, and mixtures thereof. Special preference is given totetrahydrofuran or methanol.

Temperatures are generally from −40° C. to 80° C., with preference beinggiven to a range from −20° C. to 50° C. and special preference to arange from 0° C. to 30° C. In one embodiment, the temperatures are in arange from 20 to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure or anelevated pressure of up to 6 bar and special preference being given toatmospheric pressure.

The reaction time for that reaction is generally from 1 to 60 hours,preferably from 1 to 6 hours.

In a further embodiment of the present invention (Process Variant a2),more than one reducing agent is used in Process Step a). Preference isgiven to the use of two different reducing agents in successivesub-steps of the overall reduction process. The intermediates obtainedin the first sub-step can be isolated by selecting suitable reactionconditions and may then be used in the second sub-step in order to formcompounds of formula III.

Process Variant (a2), First Sub-Step:

A suitable reducing agent for Process Variant (a2), first sub-step, is,for example, elemental iron, tin or zinc in the presence of an acid. Areducing agent to which special preference is given is elemental iron inthe presence of an acid.

In one embodiment of Process Variant (a2), first sub-step, a compound offormula II

wherein R₁ and R₂ are as defined for formula I, is reacted withelemental iron in the presence of an acid to form a compound of formulaIIA

wherein R₁ and R₂ are as defined for formula I. The compounds of formulaIIA can be isolated by selecting suitable reaction conditions and arethen used in the second sub-step of Process Variant (a2).

The compounds of formula IIA may also be used in the second sub-step ofProcess Variant (a2) directly, without being isolated.

Suitable amounts of iron for the first sub-step of Process Variant (a2)are, for example, at least 5 equivalents; preferably, from 5 to 10equivalents are used for that reaction.

Suitable acids are, for example, organic acids, such as, for example,formic acid, acetic acid or propionic acid; or inorganic acids, such as,for example, hydrochloric acid or sulfuric acid. Preference is given toorganic acids and special preference is given to acetic acid.

The reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, water; alcohols, such asmethanol, ethanol, propanol or isopropanol; or aprotic solvents, such astetrahydrofuran, tert-butyl methyl ether, dioxane, toluene or ethylacetate; and mixtures thereof; alcohols are especially preferred.

Temperatures are generally from 0° C. to 120° C., with preference beinggiven to a range from 0° C. to 100° C. and special preference to a rangefrom 20° C. to 60° C. In one embodiment, the temperatures are in a rangefrom 20 to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure.

The reaction time for that reaction is generally from 1 to 60 hours,preferably from 1 to 6 hours.

Process Variant (a2), Second Sub-Step:

In the second sub-step of Process Variant (a2), the compounds formed inthe first sub-step are reacted with a further reducing agent, which isdifferent from the reducing agent in the first sub-step, to formcompounds of formula III.

Suitable reducing agents for the second sub-step of Process Variant (a2)are the reducing agents mentioned for Process Step a).

Suitable amounts of reducing agent for the second sub-step of ProcessVariant (a2) are, for example, up to 2 equivalents; preferably, 2equivalents are used for that reaction.

The second sub-step of Process Variant (a2) is preferably carried out ina closed vessel.

In one embodiment of the process according to the invention, in whichthe second sub-step of Process Variant (a2) is carried out in a closedvessel, an excess of hydrogen is, for example, introduced into thereaction mixture in which the metal catalyst is already present. Theconsumption of hydrogen is then monitored over the course of thereaction time. In that embodiment of the process according to theinvention, the reaction is preferably stopped when the desired amount ofhydrogen has been consumed.

Suitable metal catalysts are, for example, platinum catalysts, such as,for example, platinum/carbon catalysts or PtO₂; palladium catalysts,such as, for example, Pd/C; rhodium catalysts, such as, for example,Rh/C, Rh/Al₂O₃ or Rh₂O₃; nickel catalysts, such as, for example, Raneynickel; or iridium catalysts, such as, for example, Ir(COD)Py(Pcy); andmixtures thereof. Preference is given to platinum catalysts, palladiumcatalysts, rhodium catalysts or nickel catalysts; special preference isgiven to palladium catalysts, rhodium catalysts or nickel catalysts; andvery special preference is given to Pd/C, Rh/C or Raney nickel.

Suitable amounts of metal catalyst for that reaction are, for example,from 0.001 up to 0.5 equivalent, especially from 0.01 up to 0.1equivalent.

The reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, alcohols, such as methanol,ethanol, propanol or isopropanol, or aprotic solvents, such astetrahydrofuran, tertbutyl methyl ether, dioxane, toluene or ethylacetate, and mixtures thereof. Special preference is given totetrahydrofuran or methanol.

Temperatures are generally from −40° C. to 80° C., with preference beinggiven to a range from −20° C. to 50° C. and special preference to arange from 0° C. to 30° C. In one embodiment, the temperatures are in arange from 20° C. to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure or anelevated pressure of up to 6 bar and special preference being given toatmospheric pressure.

The reaction time for that reaction is generally from 1 to 60 hours,preferably from 1 to 6 hours.

Compounds of formula II may be prepared, for example, by way of thereaction sequence which follows (see Scheme 2):

9-Alkylidene-5-nitro-benzonorbornadienes of formula II, wherein R₁ andR₂ are as defined for formula I, may be prepared by way of a Diels-Alderaddition of an in situ-generated dehydrobenzene of formula B [prepared,for example, starting from 6-nitro-anthranilic acid (compound of formulaA)] by diazotisation with a C₁₋₈alkyl nitrite, such as, for example,iso-amyl nitrite, tert-amyl nitrite, n-amyl nitrite or tert-butylnitrite, as described in L. Paquette et al., J. Amer. Chem. Soc. 99,3734 (1977), or from other suitable precursors [see H. Pellissier etal., Tetrahedron, 59, 701 (2003), R. Muneyuki and H. Tanida, J. Org.Chem. 31, 1988 (1966)], to a fulvene of formula C, wherein R₁ and R₂ areas defined for formula I. That reaction may be carried out in analogyto: R. Muneyuki and H. Tanida, J. Org. Chem. 31, 1988 (1966), P. Knochelet al., Angew. Chem. 116, 4464 (2004), J. W. Coe et al., Organic Letters6, 1589 (2004), L. Paquette et al, J. Amer. Chem. Soc. 99, 3734 (1977),R. N. Warrener et al., Molecules, 6, 353 (2001) and R. N. Warrener etal., Molecules, 6, 194 (2001). Suitable aprotic solvents for that stepare, for example, diethyl ether, butyl methyl ether, ethyl acetate,dichloromethane, acetone, tetrahydrofuran, toluene, 2-butanone ordimethoxy-ethane. Suitable reaction temperatures are from ambienttemperature to 100° C., preferably from 35° C. to 80° C.

Fulvenes of formula C may be prepared according to or in analogousmanner to:

M. Neuenschwander et al., Helv. Chim. Acta, 54, 1037 (1971), ibid 48,955 (1965), R. D. Little et al., J. Org. Chem. 49, 1849 (1984), 1. Erdenet al., J. Org. Chem. 60, 813 (1995), S. Collins et al., J. Org. Chem.55, 3395 (1990), J. Thiele, Chem. Ber. 33, 666 (1900) and Liebigs Ann.Chem. 1, 348 (1906).

Fulvenes of the general formula (C)

wherein R₁ and R₂ are as defined for formula I, may be prepared by thereaction of cyclopenta-1,3-diene with a compound of formula (F)

wherein R¹ and R² are as defined for formula I, in the presence of abase.

The reaction for the preparation of compounds of formula (C) ispreferably carried out in the presence of an inert solvent. Suitablesolvents are, for example, dimethylformamide; dimethyl sulfoxide;N-methyl-2-pyrrolidone; ethers, such as, for example, tetrahydrofuran,tertbutyl methyl ether, diethyl ether, butyl methyl ether,dimethoxyethane; alcohols, such as, for example, C₁-C₁₀alcohols, suchas, for example, methanol or ethanol; or aromatic solvents, such as, forexample, toluene, xylene or dichlorobenzene.

Suitable bases are, for example, amine bases, such as, for example,pyrrolidine, morpholine, thiomorpholine or piperidine; alkanolates, suchas, for example, sodium methanolate or sodium ethanolate, or hydroxides,such as, for example, KOH or NaOH; preference is given to pyrrolidine.

Suitable amounts of base for the reaction are, for example, from 0.01 to2 equivalents, especially from 0.25 to 0.8 equivalent.

Temperatures are generally from −20° C. to 80° C., with preference beinggiven to a range from −10° C. to ambient temperature.

The reaction time for that reaction is generally from 30 minutes to 24hours, preferably from 1 to 6 hours.

EXAMPLE A1 Preparation of 6,6-dimethylfulvene

950 g (5 equivalents) of methanol, 543 g (1.3 equivalents) of acetoneand 397 g (6 mol) of cyclopentadiene are mixed together and cooled to−5° C. 107 g (0.25 equivalent) of pyrrolidine are added. The reactionmixture is stirred for 2 hours at −5° C. The reaction is stopped byaddition of acetic acid and water. After separation of the phases, theorganic phase is extracted with saturated sodium chloride solution. Thesolvent is removed in vacuo. 535 g of 6,6-dimethylfulvene (purity: 93%;yield: 78%) are obtained.

6-Nitro-anthranilic acid is accessible, for example, in accordance withH. Seidel, Chem. Ber. 34, 4351 (1901).

Process Step b):

In one embodiment of the present invention, a single reducing agent isused in Process Step b).

A suitable reducing agent for Process Step b) is, for example, hydrogenin the presence of a metal catalyst.

Suitable amounts of reducing agent for that reaction are, for example,up to 1 equivalent, with preference being given to 1 equivalent for thatreaction. Process Step b) is preferably carried out in a closed vessel.

In an embodiment of the process according to the invention in whichProcess Step b) is carried out in a closed vessel, an excess of hydrogenis, for example, introduced into the reaction mixture in which the metalcatalyst is already present. The consumption of hydrogen is thenmonitored over the course of the reaction time. In that embodiment ofthe process according to the invention, the reaction is preferablystopped when the desired amount of hydrogen has been consumed.

Suitable metal catalysts are, for example, platinum catalysts, such as,for example, platinum/carbon catalysts (Pt/C) or PtO₂; palladiumcatalysts, such as, for example, Pd/C; rhodium catalysts, such as, forexample, Rh/C, Rh/Al₂O₃ or Rh₂O₃; nickel catalysts, such as, forexample, Raney nickel; or iridium catalysts, such as, for example,Ir(COD)Py(Pcy); and mixtures thereof. Special preference is given toPd/C or Rh/C.

Suitable amounts of metal catalyst for that reaction are, for example,from 0.001 up to 0.5 equivalent, especially from 0.01 up to 0.1equivalent.

The reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, alcohols, such as methanol,ethanol, propanol or isopropanol, or aprotic solvents, such astetrahydrofuran, tert-butyl methyl ether, dioxane, toluene, ethylacetate or dichloromethane, and mixtures thereof; special preference isgiven to tetrahydrofuran or methanol.

Temperatures are generally from −40° C. to 80° C., with preference beinggiven to a range from −20° C. to 50° C. and special preference to arange from 0° C. to 30° C. In one embodiment, the temperatures are in arange from 20° C. to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure or anelevated pressure of up to 150 bar and special preference being given toatmospheric pressure or an elevated pressure of up to 100 bar.

The reaction time for that reaction is generally from 1 to 100 hours,preferably from 1 to 24 hours.

Process Step c):

Especially suitable for use in Process Step c) are compounds of formulaV wherein Q is chlorine, fluorine, bromine or iodine and R₃ is asdefined for formula I. More especially suitable are compounds of formulaV wherein Q is chlorine, fluorine or bromine and R₃ is as defined forformula I. Outstandingly suitable are compounds of formula V wherein Qis chlorine and R₃ is as defined for formula I.

In reactions according to the invention with compounds of formula Vwherein Q is chlorine, fluorine or bromine and R₃ is as defined forformula I (Process Variant c1), compounds of formula V are used inequimolar amount, in less than equimolar amount or in excess in relationto compounds of formula IV, preferably in equimolar amount or in an upto 3-fold excess, especially preferably in equimolar amount or in an upto 1.5-fold excess, very especially preferably in equimolar amount.

The reaction of Process Variant c1) is preferably carried out in thepresence of an inert solvent. Suitable solvents are, for example,chlorobenzene, dichloromethane, chloroform, toluene, tetrahydrofuran,diethyl ether, butyl methyl ether or water, and mixtures thereof, withspecial preference being given to toluene or dichloromethane.

The reaction of Process Variant c1) is preferably carried out in thepresence of a base.

Suitable bases are, for example, amine bases, such as, for example,triethylamine or pyridine; or inorganic bases, such as carbonates, e.g.K₂CO₃ or Na₂CO₃, or hydroxides, e.g. NaOH or KOH; preference is given totrialkylamines and special preference to triethylamine.

Suitable amounts of base for the reaction are, for example, from 1 to1.5 equivalents, especially from 1 to 1.2 equivalents.

Temperatures are generally from 0° C. to 100° C., with preference beinggiven to a range from 10° C. to 50° C. and special preference to a rangefrom 15° C. to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure.

The reaction time for that reaction is generally from 1 to 48 hours,preferably from 1 to 24 hours.

Also especially suitable for use in Process Step c) are compounds offormula V wherein Q is hydroxy and R₃ is as defined for formula I.

In reactions according to the invention with compounds of formula Vwherein Q is hydroxy and R₃ is as defined for formula I (Process Variantc2), compounds of formula V are used in equimolar amount, in less thanequimolar amount or in excess in relation to compounds of formula IV,preferably in equimolar amount or in an up to 3-fold excess, especiallypreferably in equimolar amount or in an up to 1.5-fold excess, veryespecially preferably in equimolar amount.

The reactions according to the invention of Process Variant c2), thatis, with compounds of formula V wherein Q is hydroxy and R₃ is asdefined for formula I, are preferably carried out in the presence of anactivating agent.

A suitable activating agent is, for example,bis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride.

The reaction of Process Variant c2) is preferably carried out in thepresence of an inert solvent. Suitable inert solvents are, for example,dichloromethane and chloroform, and mixtures thereof; dichloromethane isespecially preferred.

The reaction of Process Variant c2) is preferably carried out in thepresence of a base.

Suitable bases are, for example, amine bases, such as, for example,triethylamine or pyridine; triethylamine is especially preferred.

Suitable amounts of base for the reaction are, for example, at least 2equivalents, especially from 2 up to 3 equivalents.

Temperatures are generally from 0° C. to 100° C., preference being givento a range from 10° C. to 50° C. and special preference to a range from15° C. to 30° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure.

The reaction time for that reaction is generally from 1 to 48 hours,preferably from 1 to 24 hours.

Also suitable for use in Process Step c) are compounds of formula Vwherein Q is C₁-C₆-alkoxy and R₃ is as defined for formula I.

Especially suitable are compounds of formula V wherein Q is methoxy orethoxy and R₃ is as defined for formula I.

In reactions according to the invention with compounds of formula Vwherein Q is C₁-C₆-alkoxy and R₃ is as defined for formula I (ProcessVariant c3), compounds of formula V are used in equimolar amount, inless than equimolar amount or in excess in relation to compounds offormula IV.

The reaction of Process Variant c3) may be carried out in the presenceof an inert solvent. Suitable solvents are, for example, chlorobenzene,dichloromethane, chloroform, toluene, tetrahydrofuran, diethyl ether orbutyl methyl ether, and mixtures thereof; chlorobenzene or toluene ispreferred as solvent.

The reaction may also be carried out in the absence of a solvent.

The reaction of Process Variant c3) is preferably carried out in thepresence of a base.

Suitable bases are, for example, amine bases, such as, for example,triethylamine or pyridine; inorganic bases, such as carbonates, e.g.K₂CO₃ or Na₂CO₃, or hydroxides, e.g. NaOH or KOH; or alkoxides, such as,for example, potassium tert-butoxide. Preference is given, for example,to potassium tertbutoxide.

Suitable amounts of base for the reaction are, for example, from 1 to1.5 equivalents, especially from 1 to 1.2 equivalents.

Temperatures are generally from 0° C. to 120° C., with preference beinggiven to a range from 50° C. to 100° C. and special preference to arange from 70° C. to 100° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure.

The reaction time for that reaction is generally from 1 to 48 hours,preferably from 1 to 24 hours.

Compounds of formula V are described in WO 04/035589 or may be preparedby way of the processes described therein.

A preferred embodiment of the process according to the invention is aprocess for the preparation of compounds of formula I wherein R₁ and R₂are methyl and R₃ is CF₂H which comprises

a) reacting a compound of formula II wherein R₁ and R₂ are methyl withhydrogen, in the presence of a rhodium/carbon catalyst, to form acompound of formula III wherein R₁ and R₂ are methyl, tetrahydrofuranbeing used as solvent; and(b) reacting that compound with hydrogen in the presence of a Raneynickel catalyst to form a compound of formula IV wherein R₁ and R₂ aremethyl, tetrahydrofuran being used as solvent; and(c) converting that compound into the compound of formula I by reactionwith a compound of formula V wherein 0 is hydroxy and R₃ is CF₂H, in thepresence of bis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride,dichloromethane being used as solvent and the reaction being carried outin the presence of triethylamine.

By selecting suitable reaction conditions for Reaction Step a), thecompound of formula III obtained in Reaction Step a) can be converted toa compound of formula IV directly, without isolation of intermediates,by complete hydrogenation. That preferred embodiment of the presentinvention is a particular advantage of the process according to theinvention.

In that preferred embodiment, more preferably a total of 5 equivalentsof reducing agent is used in the Reaction Steps a) and b) combined.

In that preferred embodiment of the present invention, hydrogen in thepresence of a metal catalyst is preferably used as reducing agent inReaction Step a) and Reaction Step b).

In that preferred embodiment of the present invention, the same metalcatalyst is preferably used in Reaction Step a) and Reaction Step b).

Suitable amounts of metal catalyst for that preferred embodiment are,for example, from 0.001 to 0.5 equivalent, especially from 0.01 to 0.1equivalent.

Preferably, the combination of the Reaction Steps a) and b) in thatpreferred embodiment of the process according to the invention iscarried out in a closed vessel. In that combination, an excess ofhydrogen is, for example, introduced into the reaction mixture in whichthe metal catalyst is already present. The consumption of hydrogen isthen monitored over the course of the reaction time. In that preferredembodiment of the process according to the invention, the reaction ispreferably stopped when the desired amount of hydrogen, which is morepreferably 5 equivalents, has been consumed.

In that embodiment, the reaction may be carried out at atmosphericpressure or at an elevated pressure of up to 150 bar, with preferencebeing given to atmospheric pressure or an elevated pressure of up to 50bar, special preference being given to atmospheric pressure or anelevated pressure of up to 20 bar, and very special preference beinggiven to atmospheric pressure or an elevated pressure of up to 6 bar.

The reaction time of that preferred embodiment of the reaction isgenerally from 1 to 100 hours, preferably from 1 to 24 hours.

The present invention is explained in greater detail by way of thefollowing Examples:

EXAMPLE P1 Preparation of 9-isopropylidene-5-amino-benzonorbornene(Compound No. Z2.11):

5.0 g of 9-isopropylidene-5-nitro-benzonorbornadiene (Comp. No. Z1.11)(22 mmol) are hydrogenated in 50 ml of tetrahydrofuran in the presenceof 1.5 g of 5% Rh/C at 25° C. and atmospheric pressure. After theabsorption of 4 equivalents of hydrogen (2.01 litres or 102% of theory)the mixture is filtered, the solvent is removed in vacuo and the residueis purified by chromatography on a silica gel column using hexane/ethylacetate (6:1) as eluant. 2.76 g of9-isopropylidene-5-amino-benzonorbornene are obtained in the form of asolid (m.p. 81-82° C.; yield: 62.9% of theory). ¹H-NMR (CDCl₃), ppm:6.90 (t, 1H), 6.67 (d, 1H), 6.46 (d, 1H), 3.77 (m, 1H), 3.73 (m, 1H),3.35 (brd, exchangeable with D₂O, 2H), 1.89 (m, 2H), 1.63 (2 s, 6H),1.26 (m, 2H). ¹³C-NMR (CDCl₃), ppm: 148.73, 147.65, 138.30, 131.75,126.19, 113.12, 110.89, 110.19, 43.97, 39.44, 26.98, 26.06, 19.85,19.75.

EXAMPLE P2 Preparation of 9-isopropylidene-5-amino-benzonorbornene(Compound No. Z2.11):

In a 1-litre steel autoclave, 5% rhodium on active carbon (43.1 g,water-moist, water content 70%) are added to 225 g of methanol. Ahydrogen pressure of 7 bar is applied and stirring is carried out atambient temperature. In the course of 2 hours, a solution of 96.7 g of9-isopropylidene-5-nitro-1,4-dihydro-1,4-methano-naphthalene in 120 g oftetrahydrofuran and 24 g of methanol is added to that mixture. Inparallel, hydrogen is taken up at a pressure of 7 bar. The reaction isstopped 30 minutes after the end of the addition. The reaction mixtureis filtered through cellulose and washed with methanol. The filtrate isconcentrated to dryness by evaporation. Methanol is added to the residueobtained. The precipitated crude product is filtered off andconcentrated to dryness by evaporation. The residue is chromatographedon silica gel using ethyl acetate/hexane (1:6).9-Isopropylidene-5-amino-benzonorbornene is obtained.

EXAMPLE P3 Preparation of 9-isopropyl-5-amino-benzonorbornene (Comp. No.Z3.11)

0.2 g of 9-isopropylidene-5-amino-benzonorbornene (72.11) ishydrogenated for 24 hours in 40 ml of tetrahydrofuran in the presence of0.1 g of RaNi (EtOH-treated) at 25° C. and 100 bar pressure. The mixtureis filtered, the solvent removed in vacuo, and the residue purified bychromatography on a silica gel column using hexane/ethyl acetate (6:1)as eluant. 9-Isopropyl-5-amino-benzonorbornene (Z3.11) is obtained inthe form of a solid (syn/anti ratio 29:71; yield: 82% of theory).

EXAMPLE P4 Preparation of 9-isopropyl-5-amino-benzonorbornene (Comp. No.Z3.11)

41.4 g of 9-isopropylidene-5-nitro-benzonorbornadiene (Comp. No. Z1.11)in 1 litre of tetrahydrofuran are hydrogenated exhaustively in thepresence of 22 g of 5% Pd/C at 25° C. under normal pressure for 4 hours.The reaction mixture is filtered, the solvent is removed in vacuo andpurification by chromatography on silica gel is carried out using ethylacetate/hexane (1:7) as eluant. 29.9 g of9-isopropyl-5-amino-benzonorbornene (Comp. No. Z3.11) (syn/anti ratio32:68; yield: 81.5% of theory) are obtained in the form of an oil. Synepimer: ¹H-NMR (CDCl₃), ppm: 6.91 (t, 1H), 6.64 (d, 1H), 6.48 (d, 1H),3.54 (brd, exchangeable with D₂O, 2H), 3.20 (m, 1H), 3.15 (m, 1H), 1.92(m, 2H), 1.53 (d, 1H), 1.18 (m, 2H), 1.02 (m, 1H), 0.81 (m, 6H); ¹³C-NMR(CDCl₃), ppm: 147.73, 140.03, 130.15, 126.41, 113.35, 112.68, 69.00,46.62, 42.06, 27.74, 26.83, 25.45, 22.32, 22.04; anti epimer: ¹H-NMR(CDCl₃), ppm: 6.89 (t, 1H), 6.63 (d, 1H), 6.46 (d, 1H), 3.55 (brd,exchangeable with D₂O, 2H), 3.16 (m, 1H), 3.13 (m, 1H), 1.87 (m, 2H),1.48 (d, 1H), 1.42 (m, 1H), 1.12 (m, 2H), 0.90 (m, 6H); ¹³C-NMR (CDCl₃),ppm: 150.72, 138.74, 133.63, 126.15, 112.94, 111.53, 68.05, 45.21,40.61, 26.25, 24.47, 23.55, 20.91 (2×). The syn/anti assignments aremade on the basis of NOE-NMR experiments.

EXAMPLE P5 Preparation of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Comp. No. A.11):

1.9 g of bis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride (7.2 mmol,1.4 equivalents) are added at ambient temperature to a solution of 1 gof 9-isopropyl-5-amino-benzonorbornene (Comp. No. Z3.11, syn/anti ratio90:10; 5 mmol), 1.7 ml of triethylamine (12.1 mmol,

2.4 equivalents) and 1.2 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid (6.2 mmol, 1.4equivalents) in 40 ml of dichloromethane and stirring is carried out for20 hours. After the addition of water and saturated NaHCO₃ solution, theorganic phase is extracted with ethyl acetate. Purification on silicagel in ethyl acetate/hexane (2:3) and subsequent crystallisation fromhexane yields 1.31 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide (m.p.124-125° C.; syn/anti ratio 92:8 according to ¹H-NMR; yield: 73%). Thecrystalline material was analyzed by differential scanning calorimetryand x-ray diffraction and was identified as crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide (seeFIG. 7).

EXAMPLE P6 Preparation of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Comp. No. A.11):

To a solution of 100 g of 9-isopropyl-5-amino-benzonorbornene (Comp. No.Z3.11, syn/anti ratio 90:10; 0.5 mol, 50% chlorobenzene solution) and55.7 g of triethylamine (0.55 mol, 1.1 equivalents) in 200 g ofchlorobenzene there are added at 40° C., in the course of 2 hours, 97.3g of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl chloride (50%chlorobenzene solution, 0.5 mol, 1 equivalent) and stirring is carriedout for 1 hour. After the addition of water and hydrochloric acid (a pHof 6-7 is established), the organic phase is extracted withchlorobenzene. The organic phase is concentrated by distilling offchlorobenzene. Following subsequent crystallisation from methanol/water(3:1 mixture), 126 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide areobtained (m.p. 124-125° C.; purity: 99.2%; syn/anti ratio 95:5 accordingto GC, yield: 70%). The crystalline material was analyzed bydifferential scanning calorimetry and x-ray diffraction and wasidentified as crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide (seeFIG. 8.

EXAMPLE P7 Preparation of 9-isopropylidene-5-nitro-benzonorbornadiene

A mixture of 110.4 g of 6-nitroanthranilic acid (0.6 mol) and 98.5 g of6,6-dimethylfulvene (1.5 equivalents) in 700 ml of dimethoxyethane areadded dropwise at 72° C. to a solution of 96.3 g of tert-butyl nitrite(1.4 equivalents) in 2 litres of 1,2-dimethoxyethane under a nitrogenatmosphere. Evolution of gas commences and the temperature of themixture rises to 79° C. The evolution of gas subsides after 30 minutes.After stirring for 3 hours at the reflux temperature of the solvent, themixture is cooled to ambient temperature. The solvent is removed invacuo and the residue is purified by chromatography on a silica gelcolumn using hexane/ethyl acetate (95:5) as eluant. 76.7 g of9-isopropylidene-5-nitro-benzonorbornadiene are obtained in the form ofa yellow solid (m.p. 94-95° C.). ¹H-NMR (CDCl₃), ppm: 7.70 (d, 1H), 7.43(d, 1H), 7.06 (t, 1H), 6.99 (m, 2H), 5.34 (brd s, 1H), 4.47 (brd s, 1H),1.57 (2 d, 6H). ¹³C-NMR (CDCl₃), ppm: 159.83, 154.30, 147.33, 144.12,142.89, 141.93, 125.23 (2×), 119.32, 105.68, 50.51, 50.44, 19.05, 18.90.

EXAMPLE P8 Preparation of 9-isopropylidene-5-nitro-benzonorbornadiene

98.5 g of 6,6-dimethylfulvene in 500 g of methyl ethyl ketone are heatedto 60° C. A solution of 182 g of 6-nitroanthranilic acid in 700 g ofmethyl ethyl ketone are added over a period of 2 hours at 60° C. under anitrogen atmosphere, and in parallel 216 g of tert-amyl nitrite areadded in the course of 2.5 hours. The solvent is removed in vacuo at 60°C. 200 g of xylene are added, and then 1200 g of hexane are added. Thesuspension obtained is filtered and washed with hexane. The solvent isremoved in vacuo at 60° C., and 200 g of methanol are added to the crudeproduct. The crude product that crystallises out is filtered off at 0°C. and washed with 100 g of methanol. After removal of the residualsolvent in vacuo at 60° C., 120 g of9-isopropylidene-5-nitro-benzonorbornadiene (m.p. 93° C.) are obtained.

EXAMPLE P9 Preparation of 9-isopropylidene-5-amino-benzonorbornadiene(Comp. No. Z4.11):

Powdered iron is added to 2.72 g of9-isopropylidene-5-nitro-benzonorbornadiene (Comp. No. Z1.11) dissolvedin 50 ml of tetrahydrofuran and 61 ml of acetic acid (5% in water) andstirring is carried out for 20 hours at 30° C. The crude product isfiltered off and ethyl acetate is added. Washing is then carried outwith aqueous NaHCO₃ solution and saturated sodium chloride solution, anddrying is carried out by addition of Na₂SO₄. The crude product ispurified on a silica gel column (eluant: 1:3 ethyl acetate:hexane). 2.01g of 9-isopropylidene-5-amino-benzonorbornadiene are obtained in theform of beige crystals (yield: 85%; m.p. 121-123° C.).

¹H-NMR (CDCl₃): 6.95 (m, 2H), 6.80 (m, 2H), 6.39 (d, 1H), 4.41 (m, 1H),4.37 (m, 1H), 3.91 (brd, exchangeable with D₂O, 2H), 1.58 (s, 3H), 1.57(s, 3H); ¹³C-NMR (CDCl₃): 160.8, 151.6, 143.0, 141.9, 139.1, 134.2,125.3, 113.2, 112.5, 101.5, 50.9, 46.3, 19.0, 18.8.

P10 Preparation of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylicAcid (9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Comp. No. A.11):

6.2 g of 9-isopropyl-5-amino-benzonorbornene (Comp. No. Z3.11, syn/antiratio 90:10; 30 mmol, 1.05 equivalents) and 1.6 g of potassiumtert-butoxide (14.7 mmol, 0.5 equivalent) are added to a solution of 6 gof 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid ethyl ester(29 mmol) in 60 ml of chlorobenzene. The reaction mixture is heated to95° C. and the chlorobenzene solvent is completely removed in vacuo. Thereaction mixture is heated to 120° C. and stirred for 20 hours. 30 ml ofchlorobenzene are then added. The organic phase is extracted twice withwater, first at low pH, then at high pH. The organic phase isconcentrated by distilling off chlorobenzene. 8 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide areobtained in the form of a brown oil (crude yield: 33%).

The preparation of starting compounds of formula V is described by thefollowing Example.

EXAMPLE A2 Preparation of3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl Chloride

69.5 g of thionyl chloride (0.58 mol, 1.17 equivalents) are added at110° C. in the course of 2 hours to a solution of 88 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid (0.5 mol) in 440g of chlorobenzene. The reaction mixture is stirred for 1 hour at 110°C. The reaction mixture is concentrated to a crude product solution. 190g of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl chloride (50% inchlorobenzene, yield: 98%) is obtained. The crude product solution isused without being further purified.

The following compounds of formula I may be prepared on the basis of theabove Examples:

TABLE 1 Compounds of formula I (I)

Comp. No. R₁ R₂ R₃ Remarks A.01 H CH₃ CF₂H syn/anti mixture A.02 H C₂H₅CF₂H syn/anti mixture A.03 H n-C₃H₇ CF₂H syn/anti mixture A.04 H i-C₃H₇CF₂H syn/anti mixture A.05 C₂H₅ i-C₃H₇ CF₂H syn/anti mixture A.06 Hn-C₄H₉ CF₂H syn/anti mixture A.07 H i-C₄H₉ CF₂H syn/anti mixture A.08 Hsec-C₄H₉ CF₂H syn/anti mixture A.09 H t-C₄H₉ CF₂H syn/anti mixture A.10H n-C₅H₁₁ CF₂H syn/anti mixture A.11 CH₃ CH₃ CF₂H syn/anti mixture A.12C₂H₅ C₂H₅ CF₂H syn/anti mixture A.13 CH₃ C₂H₅ CF₂H syn/anti mixture A.14CH₃ n-C₃H₇ CF₂H syn/anti mixture A.15 CH₃ i-C₃H₇ CF₂H syn/anti mixtureA.16 C₂H₅ i-C₃H₇ CF₂H syn/anti mixture A.17 H H CF₂H syn/anti mixtureA.18 H CH₃ CF₃ syn/anti mixture A.19 H C₂H₅ CF₃ syn/anti mixture A.20 Hn-C₃H₇ CF₃ syn/anti mixture A.21 H i-C₃H₇ CF₃ syn/anti mixture A.22 C₂H₅i-C₃H₇ CF₃ syn/anti mixture A.23 H n-C₄H₉ CF₃ syn/anti mixture A.24 Hi-C₄H₉ CF₃ syn/anti mixture A.25 H sec-C₄H₉ CF₃ syn/anti mixture A.26 Ht-C₄H₉ CF₃ syn/anti mixture A.27 H n-C₅H₁₁ CF₃ syn/anti mixture A.28 CH₃CH₃ CF₃ syn/anti mixture A.29 C₂H₅ C₂H₅ CF₃ syn/anti mixture A.30 CH₃C₂H₅ CF₃ syn/anti mixture A.31 CH₃ n-C₃H₇ CF₃ syn/anti mixture A.32 CH₃i-C₃H₇ CF₃ syn/anti mixture A.33 C₂H₅ i-C₃H₇ CF₃ syn/anti mixture A.34 HH CF₃ syn/anti mixture

Preferred compounds of formula II are listed in the following Table:

TABLE 2 Compounds of formula II (II)

Comp. No. R₁ R₂ Remarks Z1.01 H CH₃ E/Z mixture Z1.02 H C₂H₅ E/Z mixtureZ1.03 H n-C₃H₇ E/Z mixture Z1.04 H i-C₃H₇ E/Z mixture Z1.05 C₂H₅ i-C₃H₇E/Z mixture Z1.06 H n-C₄H₉ E/Z mixture Z1.07 H i-C₄H₉ E/Z mixture Z1.08H sec-C₄H₉ E/Z mixture Z1.09 H t-C₄H₉ E/Z mixture Z1.10 H n-C₅H₁₁ E/Zmixture Z1.11 CH₃ CH₃ Z1.12 C₂H₅ C₂H₅ Z1.13 CH₃ C₂H₅ E/Zmixture Z1.14CH₃ n-C₃H₇ E/Z mixture Z1.15 CH₃ i-C₃H₇ E/Zmixture Z1.16 C₂H₅ i-C₃H₇E/Zmixture Z1.17 H H

Preferred compounds of formula III are listed in the following Table:

TABLE 3 Compounds of formula III (III)

Comp. No. R₁ R₂ Remarks Z2.01 H CH₃ E/Z mixture Z2.02 H C₂H₅ E/Z mixtureZ2.03 H n-C₃H₇ E/Z mixture Z2.04 H i-C₃H₇ E/Z mixture Z2.05 C₂H₅ i-C₃H₇E/Z mixture Z2.06 H n-C₄H₉ E/Z mixture Z2.07 H i-C₄H₉ E/Z mixture Z2.08H sec-C₄H₉ E/Z mixture Z2.09 H t-C₄H₉ E/Z mixture Z2.10 H n-C₅H₁₁ E/Zmixture Z2.11 CH₃ CH₃ Z2.12 C₂H₅ C₂H₅ Z2.13 CH₃ C₂H₅ E/Z mixture Z2.14CH₃ n-C₃H₇ E/Z mixture Z2.15 CH₃ i-C₃H₇ E/Z mixture Z2.16 C₂H₅ i-C₃H₇E/Z mixture Z2.17 H H

Preferred compounds of formula IV are listed in the following Table:

TABLE 4 Compounds of formula IV (IV)

Comp. No. R₁ R₂ Remarks Z3.01 H CH₃ syn/anti mixture Z3.02 H C₂H₅syn/anti mixture Z3.03 H n-C₃H₇ syn/anti mixture Z3.04 H i-C₃H₇ syn/antimixture Z3.05 C₂H₅ i-C₃H₇ syn/anti mixture Z3.06 H n-C₄H₉ syn/antimixture Z3.07 H i-C₄H₉ syn/anti mixture Z3.08 H sec-C₄H₉ syn/antimixture Z3.09 H t-C₄H₉ syn/anti mixture Z3.10 H n-C₅H₁₁ syn/anti mixtureZ3.11 CH₃ CH₃ syn/anti mixture Z3.12 C₂H₅ C₂H₅ syn/anti mixture Z3.13CH₃ C₂H₅ syn/anti mixture Z3.14 CH₃ n-C₃H₇ syn/anti mixture Z3.15 CH₃i-C₃H₇ syn/anti mixture Z3.16 C₂H₅ i-C₃H₇ syn/anti mixture Z3.17 H Hsyn/anti mixture

Preferred compounds of formula IIA are listed in the following Table:

TABLE 5 Compounds of formula IIA (IIA)

Comp. No. R₁ R₂ Remarks Z4.01 H CH₃ E/Z mixture Z4.02 H C₂H₅ E/Z mixtureZ4.03 H n-C₃H₇ E/Z mixture Z4.04 H i-C₃H₇ E/Z mixture Z4.05 C₂H₅ i-C₃H₇E/Z mixture Z4.06 H n-C₄H₉ E/Z mixture Z4.07 H i-C₄H₉ E/Z mixture Z4.08H sec-C₄H₉ E/Z mixture Z4.09 H t-C₄H₉ E/Z mixture Z4.10 H n-C₅H₁₁ E/Zmixture Z4.11 CH₃ CH₃ Z4.12 C₂H₅ C₂H₅ Z4.13 CH₃ C₂H₅ E/Z mixture Z4.14CH₃ n-C₃H₇ E/Z mixture Z4.15 CH₃ i-C₃H₇ E/Z mixture Z4.16 C₂H₅ i-C₃H₇E/Z mixture Z4.17 H H

The starting materials for the process of the present invention aredistinguished by ease of availability and good handling properties andare moreover reasonably priced.

In an especially preferred embodiment (bb) of the present invention, thereducing agent used in Step (b) is hydrogen in the presence of a rhodiumcatalyst.

That especially preferred embodiment (bb) makes it possible to preparein simple manner compounds of formula I in which the ratio of synisomers of formula Ia to anti isomers of formula Ib is significantlyhigher than that described in WO 04/035589; generally, syn/anti ratiosof the prepared 9-monosubstituted pyrazolyl-4-carboxylic acidbenzonorbornen-5-yl-amides of more than 90:10 are achieved.

The reaction sequence described in WO 04/035589 (Scheme 1) yields asyn:anti ratio of 9-monosubstituted pyrazolyl-4-carboxylic acidbenzonorbornene fungicides in favour of the anti isomer. Working up ofthe individual syn/anti isomers in accordance with the state of the artis generally carried out using customary methods, such as, for example,chromatographic methods.

In contrast thereto, according to the especially preferred embodiment(bb) of the present process there are prepared, in simple manner,compounds of formula I wherein the ratio of compounds of formula Ia(syn) to compounds of formula Ib (anti) is from 90:10 to 99:1.

It is therefore a particular advantage of the especially preferredembodiment (bb) of the present process that mixtures of compounds offormula I can be prepared in simple manner that have a syn/anti ratiostrongly in favour of the syn isomer.

In the context of the present invention, a “mixture of compounds offormula I that has a syn/anti ratio strongly in favour of the synisomer” is understood to be a mixture of compounds of formula I whereinthe ratio of compounds of formula Ia (syn) to compounds of formula Ib(anti) is from 90:10 to 99:1.

In the process according to the invention, the syn/anti proportion ofthe end products of the process, the 9-monosubstitutedpyrazolyl-4-carboxylic acid benzonorbornen-5-yl-amides of formula I, issubstantially determined by the syn/anti proportion of the5-amino-benzo-norbornenesk of formula IV formed when Process Step (b) iscarried out.

On carrying out Process Step (c), the amidation of the5-amino-benzonorbornenes to form the end products of the process, thecompounds of formula I, the syn proportion remains substantiallyunchanged.

After carrying out Process Step (c), the syn proportion of the compoundsof formula I can be increased by means of fractional crystallisationusing suitable solvents, for example using a tert-butyl methylether/hexane mixture or methanol as solvent.

In that especially preferred embodiment (bb) of the process according tothe invention, the compounds of formula III obtained according toProcess Step (a)

wherein R₁ and R₂ are as defined for formula I, are reactedbb) with hydrogen in the presence of a rhodium catalyst to form acompound of formula IV

wherein R₁ and R₂ are as defined for formula I and wherein the ratio ofcompounds of formula IVa (syn) to compounds of formula IVb (anti) ismore than 90:10. Those compounds are then used in Process Step (c).

After carrying out Process Step (c), the syn proportion is substantiallyunchanged. That especially preferred process variant accordingly resultsin compounds of formula I wherein the ratio of compounds of formula Ia(syn) to compounds of formula Ib (anti) is more than 90:10.

Process Step bb):

Suitable rhodium catalysts are, for example, Rh/C, RhAl₂O₃ or Rh₂O₃ andmixtures thereof. Special preference is given to Rh/C.

The reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, alcohols, such as methanol,ethanol, propanol or isopropanol, or aprotic solvents, such astetrahydrofuran, tert-butyl methyl ether, ethyl acetate, dioxane ortoluene, and mixtures thereof; special preference is given to ethanol ormethanol.

The temperatures are generally from 0° C. to 80° C., with preferencebeing given to a range from 0° C. to 25° C.

The reaction time for that reaction is generally from 1 to 100 hours,preferably from 1 to 24 hours.

Also, in the especially preferred embodiment (bb) of the presentinvention, by selecting suitable reaction conditions for Reaction Stepa), the compound of formula III obtained in Reaction Step a) can bereacted to form a compound of formula IV directly, without isolation ofintermediates, by complete hydrogenation. That very especially preferredembodiment of the present invention is a very special advantage of theprocess according to the invention. In that preferred arrangement of theembodiment (bb), a total of 5 equivalents of reducing agent ispreferably used in Reaction Steps a) and b) combined.

In that preferred arrangement of the embodiment (bb), the same metalcatalyst is preferably used in Reaction Step a) and Reaction Step b).

Suitable amounts of metal catalyst for that preferred arrangement ofembodiment (bb) are, for example, from 0.001 up to 0.5 equivalent,especially from 0.01 up to 0.1 equivalent. The combination of Reactionsteps a) and b) in that preferred arrangement of the embodiment (bb) ispreferably carried out in a closed vessel. In that arrangement an excessof hydrogen is, for example, introduced into the reaction mixture inwhich the metal catalyst is already present. The consumption of hydrogenis then monitored over the course of the reaction time. In thatpreferred arrangement of embodiment (bb), the reaction is preferablystopped when the desired amount of hydrogen, which is more preferably 5equivalents, has been consumed.

In that preferred arrangement of embodiment (bb), the reaction may becarried out at atmospheric pressure or at an elevated pressure of up to150 bar, with preference being given to atmospheric pressure or anelevated pressure of up to 50 bar, special preference being given toatmospheric pressure or an elevated pressure of up to 20 bar, and veryspecial preference being given to atmospheric pressure or an elevatedpressure of up to 6 bar.

The reaction time of that preferred embodiment of the reaction isgenerally from 1 to 100 hours, preferably from 1 to 24 hours

The above-described especially preferred embodiment (bb) of the processaccording to the invention is explained in greater detail by way of thefollowing Example:

EXAMPLE P11 Preparation of 9-isopropyl-5-amino-benzonorbornene (Comp.No. Z3.11)

95 g (0.42 mol) of 9-isopropylidene-5-nitro-benzonorbornadiene (Z1.11)in 1 litre of tetrahydrofuran are exhaustively hydrogenated at 25° C.under normal pressure in the presence of 50 g of 5% Rh/C. After 3½ days,the absorption of hydrogen comes to an end. The reaction mixture isfiltered, the solvent is removed in vacuo, and purification bychromatography is carried out on silica gel using ethyl acetate/hexane(1:4) as eluant. 71.8 g (85% of theory) of9-isopropyl-5-amino-benzonorbornene are obtained in the form of an oilwith a syn/anti ratio of 92:8 according to ¹H-NMR.

The compounds of formula IV

wherein R₁ and R₂ are as defined for formula I, and wherein the ratio ofcompounds of formula IVa (syn)

wherein R₁ and R₂ are as defined for formula I, to compounds of formulaIVb (anti)

wherein R₁ and R₂ are as defined for formula I, is from 90:10 to 99:1,are valuable intermediates in the preparation of compounds of formula Iand have been developed specifically for the present process accordingto the invention. The present invention accordingly relates alsothereto.

There are especially valuable in the preparation of compounds of formulaI especially those compounds of formula IV wherein the ratio ofcompounds of formula IVa (syn) to compounds of formula IVb (anti) isfrom 91:9 to 99:1.

There are very especially valuable in the preparation of compounds offormula I especially those compounds of formula IV wherein the ratio ofcompounds of formula IVa (syn) to compounds of formula IVb (anti) isfrom 92:8 to 98:2.

There are very especially valuable in the preparation of compounds offormula I especially those compounds of formula IV wherein the ratio ofcompounds of formula IVa (syn) to compounds of formula IVb (anti) isapproximately 95:5.

Especially suitable as intermediates in the preparation of compounds offormula I are compounds of formula IV wherein R₁ and R₂ are methyl.

As described in Scheme 2,6-nitro-anthranilic acid (compound of formula Ain Scheme 2) may be used in the preparation of compounds of formula II.It has been found that 6-nitro-anthranilic acid can be prepared simplyand in a high regioselective yield in accordance with the followingscheme (Scheme 3):

In that scheme, 3-nitro-phthalimide (compound of formula E) is convertedby reaction with an aqueous base, such as, for example, aqueous sodiumhydroxide, and by subsequent reaction with an aqueous acid, such as, forexample, aqueous hydrochloric acid, into 6-nitrophthalamic acid(compound of formula D). 6-Nitrophthalamic acid is obtained in a highregioselective yield; typically, more than 70% measured relative to thestarting material 3-nitro-phthalimide is achieved.

In a second step, 6-nitrophthalamic acid is then converted to thedesired 6-nitro-anthranilic acid (compound of formula A). In that step,6-nitrophthalamic acid may, for example, be reacted first with aqueousbase, such as, for example, aqueous sodium hydroxide, and sodiumhypochlorite, and then with aqueous acid, such as, for example, aqueoushydrochloric acid.

3-Nitro-phthalimide is commercially available.

Scheme 2 is explained in greater detail by way of the following Example:

EXAMPLE A3 Preparation of 6-nitro-anthranilic Acid a) Preparation of6-nitrophthalamic Acid

A suspension of 57.6 g of 3-nitro-phthalimide (0.3 mol) in 672 g ofwater is cooled to 5° C. 80 g of 30% sodium hydroxide solution (0.6 mol,2 equivalents) are added in the shortest possible time. After 2 hours at5° C., the reaction mixture is added at 5° C. to 65 g of 32%hydrochloric acid solution (0.57 mol, 1.9 equivalents), which is dilutedbeforehand with 72 ml of water. The pH value is adjusted to 2-2.5 andthe crude product which crystallises out is filtered off and washedtwice with water. 6-Nitrophthalamic acid is obtained in a yield of 73%.

b) Preparation of 6-nitro-anthranilic Acid

A suspension of 126.3 g of 6-nitrophthalamic acid (0.6 mol) in 429 g ofwater is cooled to 5° C. 80 g of 30% sodium hydroxide solution (0.6 mol,1 equivalent) are added in the course of 0.5 hour at 5° C.

The reaction mixture together with 288 g of 15.2% sodium hypochloritesolution (0.6 mol, 1 equivalent) is slowly added to a sodium hydroxidesolution (235.2 g of 30% sodium hydroxide solution (1.76 mol, 3equivalents), diluted with 280 g of water) preheated to 43° C. Thetemperature is maintained at 40-45° C. during the addition. After 1 hourat 40-45° C., the reaction mixture is added to a mixture of 268 g of 32%hydrochloric acid (2.35 mol, 3.9 equivalents) and 200 g of water. Thetemperature is maintained at 20-45° C. during the addition. The crudeproduct which crystallises out is filtered off and washed three timeswith water. 6-Nitro-anthranilic acid is obtained in a yield of 70%.

The present invention relates furthermore to a process for thepreparation of compounds of formula IV

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, which comprisesa) reacting a compound of formula II

wherein R₁ and R₂ are as defined for formula IV, with at least onereducing agent to form a compound of formula III

wherein R₁ and R₂ are as defined for formula IV; and(b) converting that compound with at least one reducing agent into thecompound of formula IV.

In that process according to the invention for the preparation ofcompounds of formula IV, sub-step (a) (preparation of compounds offormula II) and sub-step (b) (preparation of compounds of formula IV)are carried out as described above.

Also in that process according to the invention for the preparation ofcompounds of formula IV, by selecting suitable reaction conditions forReaction Step a), the compound of formula III obtained in Reaction Stepa) can be reacted, for example in the manner described above, to form acompound of formula IV directly, without isolation of intermediates, bycomplete hydrogenation.

The present invention relates furthermore to a process for thepreparation of compounds of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, which comprisesaa) reacting 6-nitro-anthranilic acid with a nitrite, selected fromisoamyl nitrite and tert-butyl nitrite, and with a compound of formula C

wherein R₁ and R₂ are as defined for formula I, to form a compound offormula II

wherein R₁ and R₂ are as defined for formula I, anda) reacting that compound with a reducing agent to form a compound offormula III

wherein R₁ and R₂ are as defined for formula I; and(b) reacting that compound with a reducing agent to form a compound offormula IV

wherein R₁ and R₂ are as defined for formula I; and(c) converting that compound into the compound of formula I by reactionwith a compound of formula V

wherein Q is chlorine, bromine, iodine or hydroxy and R₃ is as definedfor formula I.

In that process for the preparation of compounds of formula I, theReaction Steps (a), (b) and (c) are carried out in the manner describedabove. Suitable aprotic solvents for Reaction Step (aa) are, forexample, diethyl ether, butyl methyl ether, ethyl acetate,dichloromethane, acetone, tetrahydrofuran, toluene, 2-butanone ordimethoxyethane. Suitable reaction temperatures for Reaction Step (aa)are from ambient temperature to 100° C., preferably from 35 to 80° C.

An especially preferred embodiment of that process is a process for thepreparation of compounds of formula I wherein R₁ and R₂ are methyl andR₃ is CF₂H which comprises (aa) reacting 6-nitro-anthranilic acid withtert-butyl nitrite and with a compound of formula C wherein R₁ and R₂are methyl to form a compound of formula II wherein R₁ and R₂ aremethyl; and

a) reacting that compound with hydrogen in the presence of arhodium/carbon catalyst to form a compound of formula III wherein R₁ andR₂ are methyl; and(b) reacting that compound with hydrogen in the presence of a Raneynickel catalyst to form a compound of formula IV wherein R₁ and R₂ aremethyl; and(c) converting that compound into the compound of formula I by reactionwith a compound of formula V wherein 0 is hydroxy and R₃ is CF₂H, in thepresence of an activating agent, preferably in the presence ofbis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride, the reaction beingcarried out in the presence of a base, preferably in the presence oftriethylamine.

A more especially preferred embodiment of that process is a process forthe preparation of compounds of formula I wherein R₁ and R₂ are methyland R₃ is CF₂H which comprises

(aa) reacting 6-nitro-anthranilic acid with tert-butyl nitrite and witha compound of formula C wherein R₁ and R₂ are methyl to form a compoundof formula II wherein R₁ and R₂ are methyl, dimethoxyethane being usedas solvent, anda) reacting that compound with hydrogen in the presence of arhodium/carbon catalyst to form a compound of formula III wherein R₁ andR₂ are methyl, tetrahydrofuran being used as solvent; and(b) reacting that compound with hydrogen in the presence of a Raneynickel catalyst to form a compound of formula IV wherein R₁ and R₂ aremethyl, tetrahydrofuran being used as solvent; and(c) converting that compound into the compound of formula I by reactionwith a compound of formula V wherein Q is hydroxy and R₃ is CF₂H, in thepresence of bis(2-oxo-3-oxazolidinyl)-phosphinic acid chloride,dichloromethane being used as solvent and the reaction being carried outin the presence of triethylamine.

The compounds of formula II

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, are new and have been developed specifically for carryingout the process according to the invention. The present inventionaccordingly relates also to compounds of formula II wherein R₁ and R₂are each independently of the other hydrogen or C₁-C₅alkyl. Specialpreference is given to compounds of formula II wherein R₁ and R₂ aremethyl.

Some of the compounds of formula III

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, are new and have been developed specifically for carryingout the process according to the invention. The present inventionaccordingly relates also to compounds of formula II wherein R₁ and R₂are each independently of the other hydrogen or C₁-C₅alkyl, with theexception of 9-isopropyl-idene-5-amino-benzonorbornene.

Some of the compounds of formula IV

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, are new and have been developed specifically for carryingout the process according to the invention. The present inventionaccordingly relates also to compounds of formula IV wherein R₁ and R₂are each independently of the other hydrogen or C₁-C₅alkyl, with theexception of 9-isopropyl-5-amino-benzonorbornene.

The compounds of formula IIA

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, are new and have been developed specifically for carryingout the process according to the invention. The present inventionaccordingly relates also to compounds of formula IIA wherein R₁ and R₂are each independently of the other hydrogen or C₁-C₅alkyl. Specialpreference is given to compounds of formula IIA wherein R₁ and R₂ aremethyl.

Further, compounds of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, may also be prepared using compoundsof formula VI

wherein L is a C₁-C₆alkylene chain and R₃ is as defined for formula I,byd) reacting a compound of formula Va

wherein Q₁ is chlorine, fluorine, bromine, iodine or C₁-C₆alkoxy and R₃is as defined for formula I, with a compound of formula VII

HO-L-OH  (VII),

wherein L is as defined for formula VI, to form a compound of formulaVI; ande) converting that compound into the compound of formula I by reactionwith a compound of formula IV

wherein R₁ and R₂ are as defined for formula I. In that process,compounds of formula IV may be prepared in the manner described above.The present invention relates also to that preparation of compounds offormula I using compounds of formula VI and carrying out Process Steps(d) and (e).

The alkylene chains in the definitions of the substituents of thecompounds of formula VI may be straight or branched and are, forexample, a methylene chain or an ethylene chain, or straight or branchedC₃-C₆alkylene chains, such as —CH₂—CH₂—CH₂— as a straight C₃alkylenechain or —CH₂—C(CH₃)₂—CH₂— as a branched C₅alkylene chain.

Process Step d):

Especially suitable for use in Process Step d) are compounds of formulaVa wherein Q₁ is chlorine, fluorine, bromine or iodine and R₃ is asdefined for formula I. Very especially preferred are compounds offormula Va wherein Q₁ is chlorine and R₃ is as defined for formula I.

Especially suitable for use in Process Step d) are compounds of formulaVII wherein L is an ethylene chain.

In the reactions according to the invention, compounds of formula Va areused, for example, in equimolar amounts or in excess in relation tocompounds of formula VII, preferably in an up to 4-fold excess,especially preferably in a 2-fold to 4-fold excess, very especiallypreferably in a 2-fold excess.

The reaction is preferably carried out in the presence of an inertsolvent. Suitable solvents are, for example, chlorobenzene,dichloromethane, chloroform, toluene, tetrahydrofuran, diethyl ether,butyl methyl ether or water, and mixtures thereof, with specialpreference being given to chlorobenzene.

The reaction is preferably carried out in the presence of a base.

Suitable bases are, for example, amine bases, such as, for example,triethylamine or pyridine; or inorganic bases, such as carbonates, e.g.K₂CO₃ or Na₂CO₃, or hydroxides, e.g. NaOH or KOH, with preference beinggiven to trialkylamines and special preference to triethylamine.

Suitable amounts of base for the reaction are, for example, from 1 up to1.5 equivalents, especially from 1 up to 1.2 equivalents.

The temperatures are generally from 0° C. to 150° C., with preferencebeing given to a range from 50° C. to 100° C. and special preference toa range from 60° C. to 100° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure.

The reaction time for that reaction is generally from 1 to 48 hours,preferably from 1 to 24 hours.

Compounds of formula VII are commercially available or can be preparedaccording to known processes.

Process Step e):

In the reactions according to the invention, compounds of formula IV areused, for example, in equimolar amounts or in excess in relation tocompounds of formula VI, preferably in an up to 4-fold excess,especially preferably in a 2-fold to 4-fold excess, very especiallypreferably in a 2-fold excess.

The reaction may be carried out in the presence of an inert solvent.Suitable solvents are, for example, chlorobenzene, dichloromethane,chloroform, toluene, xylene, tetrahydrofuran, diethyl ether or butylmethyl ether, and mixtures thereof, with special preference being givento chlorobenzene.

The reaction may also be carried out in the absence of a solvent.

The reaction is preferably carried out in the presence of a base.

Suitable bases are, for example, amine bases, such as, for example,triethylamine or pyridine; inorganic bases, such as carbonates, e.g.K₂CO₃ or Na₂CO₃, or hydroxides, e.g. NaOH or KOH; or alkoxides, such as,for example, potassium tert-butoxide, with preference being given, forexample, to potassium tert-butoxide.

Suitable amounts of base for the reaction are, for example, from 1 up to1.5 equivalents, especially from 1 up to 1.2 equivalents.

The temperatures are generally from 0° C. to 150° C., with preferencebeing given to a range from 50° C. to 150° C. and special preference toa range from 80° C. to 120° C.

The reaction may be carried out at atmospheric pressure or at elevatedpressure, with preference being given to atmospheric pressure.

The reaction time for that reaction is generally from 1 to 48 hours,preferably from 1 to 24 hours.

The above-described process, to which the present invention alsorelates, is explained with reference to the following Examples:

EXAMPLE P12 Preparation of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid2-(3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyloxy)-ethyl Ester(Comp. No. Z4.02):

6.2 g of ethylene glycol (0.1 mol, 0.5 equivalent), 22.2 g oftriethylamine (0.22 mmol, 1.1 equivalents) and 50 ml of chlorobenzeneare added at ambient temperature to a 49% solution of 38.9 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl chloride (0.2 mol) inchlorobenzene. The reaction mixture is stirred for 5 hours at 80° C.Water is added and the organic phase is extracted with methyl isobutylketone. 7 g of active carbon are added and the reaction mixture isfiltered. The organic phase is concentrated. 35.9 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid2-(3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyloxy)-ethyl ester(yield: 95%) are obtained. ¹H-NMR (CDCl₃), ppm: 7.91 (s, 2H), 7.06 (t,2H), 4.55 (s, 4H), 3.96 (s, 6H).

EXAMPLE P13 Preparation of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Comp. No. A.11):

6.9 g of 9-isopropyl-5-amino-benzonorbornene (Comp. No. Z3.11, syn/antiratio 90:10; 32.8 mmol, 2.05 equivalents) and 1.9 g of potassiumtert-butoxide (16 mmol, 1 equivalent) are added to a solution of 6 g (16mmol) of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid2-(3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyloxy)-ethyl ester(Comp. No. Z4.02, prepared according to Example P12) in 60 ml ofchlorobenzene. The reaction mixture is heated to 95° C. and the solventchlorobenzene is completely removed in vacuo. The reaction mixture isheated to 120° C. and stirred for 20 hours. 30 ml of chlorobenzene arethen added. The organic phase is extracted twice with water, first atlow pH, then at high pH. The organic phase is concentrated by distillingoff chlorobenzene. 8 g of3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide areobtained in the form of a brown oil (crude yield: 51%).

Preferred compounds of formula VI are listed in the following Table.

TABLE 6 Compounds of formula VI (VI)

Comp. No. R₃ L Z4.01 CF₂H —CH₂— Z4.02 CF₂H —CH₂—CH₂— Z4.03 CF₂H—CH₂—CH₂—CH₂— Z4.04 CF₂H —CH₂—CH₂—CH₂—CH₂— Z4.05 CF₃ —CH₂— Z4.06 CF₃—CH₂—CH₂— Z4.07 CF₃ —CH₂—CH₂—CH₂— Z4.08 CF₃ —CH₂—CH₂—CH₂—CH₂—

The compounds of formula VI are distinguished by ease of availabilityand good handling properties and are moreover reasonably priced.

The compounds of formula VI

wherein L is a C₁-C₆alkylene chain and R₃ is CF₃ or CF₂H, are new andhave been developed specifically for carrying out the process accordingto the invention. The present invention accordingly relates also tocompounds of formula VI wherein L is a C₁-C₆alkylene chain and R₃ is CF₃or CF₂H. Preference is given to compounds of formula VI wherein L is anethylene chain. Preference is given to compounds of formula VI whereinR₃ is CF₂H. Special preference is given to compounds of formula VIwherein L is an ethylene chain and R₃ is CF₂H.

For a better overview, the above-mentioned reactions are summarised inScheme 4.

As stated above, the invention relates in various aspects inter alia to:

(1) the preparation of compounds of formula I starting from compounds offormula II using Steps a), b) and c);(2) the preparation of compounds of formula I starting from compounds offormula II using Steps a2), b) and c);(3) the preparation of compounds of formula IV starting from compoundsof formula II using Steps a) and b);(4) the preparation of compounds of formula IV starting from compoundsof formula II using Steps a2) and b);(5) the preparation of compounds of formula I starting from compounds offormula A using Steps aa), a), b) and c);(6) the preparation of compounds of formula I starting from compounds offormula A using Steps aa), a2), b) and c);(7) the preparation of compounds of formula I starting from compounds offormula II using Steps a), b), d) and e); and(8) the preparation of compounds of formula I starting from compounds offormula II using Steps a2), b), d) and e).

The invention relates also to intermediates for use in the aboveprocesses.

The present invention further relates to a novel crystal modification ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,compositions comprising it and to the use thereof in the control offungus infestation in cultivated plants.

3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Comp. No. A.11) is effective against a number of diseases caused byphytopathogenic fungi. This amide is a chiral molecule which can occurin 4 stereoisomeric forms, shown as enantiomers of formulae A.11 (syn1),A.11 (syn2), A.11 (anti1) and A.11 (anti2):

According to the invention“syn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide”means a racemic mixture of compounds of formula A.11 (syn1) andcompounds of formula A.11 (syn2). Crystalline material ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amidehaving a single melting point of 110-112° C. (diastereomeric purity:90%) is disclosed in WO 04/035589. This crystalline material is definedherein as “crystal modification A” ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide.

Various crystal modifications of chemical compounds can exhibit verydifferent physical properties, which may lead to unforseeable problemsduring technical preparation and processing of these compounds. Thecharacteristics of crystal modifications frequently have a crucialinfluence on the separating ability (filtration), stirrability (crystalvolume), surface activity (foaming), rate of drying, solubility,quality, formulating ability and storage stability and bioefficacy offor example pharmaceutically and agronomically active compounds. Forexample, the grinding and formulating properties (e.g. granulating) ofproducts may be completely different, depending on the respectivecrystal modification. Since, depending on the envisaged formulatingprocess, different physical properties of the respective products are ofimportance, it is especially advantageous to find the optimally suitedcrystal form for the respective formulating process.

Furthermore, a modification can suddenly transform into anotherundesired modification under certain thermodynamic conditions. Thenumber of polymorphic states are unpredictable. The most stablepolymeric state may not form because the rate of formation of newcrystals from a solution may be extremely slow.

It is therefore the aim of the present invention to specifically providenovel crystal modifications ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide withgood properties in relation to the formulation of the active ingredientand its storability.

The present invention relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,wherein said crystal modification is characterized by an x-ray powderdiffraction pattern, expressed in terms of d-spacings and relativeintensities, wherein said an x-ray powder diffraction pattern comprisesthe following characteristic lines: 13.42 Å (strong), 9.76 Å (medium),6.93 Å (medium), 6.74 Å (medium), 4.79 Å (medium), 4.73 Å (medium), and3.66 Å (medium). The x-ray powder diffraction pattern has been obtainedby using a Bruker-AXS D8 Advanced Powder X-ray diffractometer, source:Cu Kα1.

Crystal modification B differs from crystal modification A with respectto thermodynamic stability, physical parameters, such as the absorptionpattern of IR and Raman spectra, in x-ray structure investigations andin their solubility in water or other commonly used liquid carriers inagrochemical formulations.

The modification B has significant advantages compared with themodification A. Thus, for example, DSC, solubility tests and otherexperiments, have shown that the modification B surprisingly hassubstantially better thermodynamic stability than the modification A.

For example, the water solubility of modification B is lower than thewater solubility of modification A over relevant temperature ranges. Inaqueous dispersions the polymorph with the lowest solubility is moststable. A polymorph with a higher solubility is unstable, because thesurrounding water phase will be supersaturated relative to the morestable polymorph leading to solution of the more unstable polymorph andcrystallisation of the more stable polymorph. The resulting change ofparticle sizes could lead to a change of the stability of the formulateddispersion.

It is particularly important for a fungicide that its agrochemicalformulation ensures high and reproducible stability over a long period.These preconditions are fulfilled by incorporation of the compoundsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide ofthe crystal modification B, owing to its high thermodynamic stabilitycompared with crystal modification A. In particular, this is displayedin a solid agrochemical dosage form. If an active ingredient issubjected to a conversion process, this may readily also affect thestability of the solid formulation.

Accordingly, agrochemical active ingredients or polymorphic formsthereof which are of primary interest for development of new activeingredients are those which exhibit high stability and do not have theabove-mentioned disadvantages. The crystal modification B fulfills thesepreconditions.

Crystal modification B was prepared as described in examples P5, P6 andP14. Crystal modification A was prepared as described in example A4.Crystal modification B can also be prepared by seeded crystallisationfrom methanol/water mixtures; typically, a 10% seed loading can be used.For example, crystal modification B can also be prepared by seededcrystallisation from 20% water/methanol.

Modification B has an X-ray powder pattern with characteristic lineswith interplanar spacings (d values in Angstrom) of 13.42 Å (strong),9.76 Å (medium), 6.93 Å (medium), 6.74 Å (medium), 4.79 Å (medium), 4.73Å (medium), and 3.66 Å (medium) (see table 7 or FIG. 1). In contrast,modification A has an X-ray powder pattern with characteristic lineswith interplanar spacings (d values) of 21.98 Å (medium), 10.81 Å(weak), 8.79 Å (weak), 6.51 Å (weak), 4.65 Å (medium) and 4.20 Å(medium) (see table 8 or FIG. 2). The x-ray powder diffraction patternshave been obtained by using a Bruker-AXS D8 Advanced Powder X-raydiffractometer, source: Cu Kα1.

TABLE 7 Characterization of the modification B (X-ray powder pattern)2-Theta d-Spacing (Å) Strength 6.59 13.42 strong 9.08 9.76 medium 12.856.93 medium 13.22 6.74 medium 14.21 6.23 weak 15.65 5.66 medium 18.324.84 medium 18.77 4.79 medium 19.02 4.73 medium 22.31 3.98 medium 23.353.81 medium 24.88 3.66 medium

TABLE 8 Characterization of the modification A (X-ray powder pattern)2-Theta d-Spacing (Å) Strength 4.02 21.98 medium 6.48 13.64 weak 8.1910.81 weak 9.06 9.76 weak 10.09 8.79 medium 11.63 7.60 medium 12.74 9.94weak 13.68 6.51 weak 14.40 6.15 weak 18.63 4.76 weak 19.35 4.65 medium20.96 4.23 medium

In the Raman Spectrum modification B differs from modification A in theshape and in the relative intensity of many bands (see FIGS. 3 and 4).For example, the apparatus Thermo Electron Almega Raman Microscope (785nm, High Resolution settings) can be used for the recording of each ofthe Raman Spectra.

Characteristic for modification B is also the thermogram in DSC(differential scanning calorimetry, see FIG. 5). It has an endothermicpeak in the range from 120° C. to 128° C. depending on purity. Forexample, crystal modification B in pure form has a peak temperature of128° C. and an endothermic signal around 90 J/g. This thermogram ischaracteristically different from the thermogram of the modification A(see FIG. 6), which has an endothermic peak at about 112° C. and anendothermic signal of 76 J/g. The measurement was carried out on aMetler Toledo 820 DSC in a closed pan with a heating rate of 10K/minute. The typical sample quantity is about 5 mg.

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,wherein said crystal modification is characterized by an x-ray powderdiffraction pattern, expressed in terms of d-spacings and relativeintensities, wherein said an x-ray powder diffraction pattern comprisesthe following characteristic lines: 13.42 Å (strong), 9.76 Å (medium),6.93 Å (medium), 6.74 Å (medium), 6.23 Å (weak), 5.66 Å (medium), 4.84 Å(medium), 4.79 Å (medium), 4.73 Å (medium), 3.98 Å (medium), 3.81 Å(medium) and 3.66 Å (medium).

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,wherein said crystal modification is characterized having the x-raypowder diffraction pattern depicted in FIG. 1.

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,wherein said crystal modification is characterized by having in thethermogram in differential scanning calorimetry an endothermic signalwith a peak in the range from 120° C. to 128° C.

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide insubstantially pure form. According to the invention “substantially pure”means preferably at least 75% by weight of crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide),more preferably at least 80% by weight.

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide inpure form. According to the invention “pure” means at least 90% byweight of crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide, morepreferably at least 95% by weight, even more preferably at least 98% byweight.

The present invention preferably relates to crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide inhighly pure form. According to the invention “highly pure” meanssubstantially homogenous crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide.

The crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide canbe used against microorganisms, that cause diseases on useful plants, inparticular against phytopathogenic fungi. The crystal modification B iseffective especially against phytopathogenic fungi belonging to thefollowing classes: Ascomycetes (e.g. Venturia, Podosphaera, Erysiphe,Monilinia, Mycosphaerella, Uncinula); Basidiomycetes (e.g. the genusHemileia, Rhizoctonia, Phakopsora, Puccinia, Ustilago, Tilletia); Fungiimperfecti (also known as Deuteromycetes; e.g. Botrytis,Helminthosporium, Rhynchosporium, Fusarium, Septoria, Cercospora,Alternaria, Pyricularia and Pseudocercosporella); Oomycetes (e.g.Phytophthora, Peronospora, Pseudoperonospora, Albugo, Bremia, Pythium,Pseudosclerospora, Plasmopara).

According to the invention “useful plants” typically comprise thefollowing species of plants: pome fruits; stone fruits; grapes;strawberries; tomatoes; potatoes; peppers; lettuce; sugarbeets; peanuts;wheat; rye; barley; triticale; oats; rice; maize; cotton; soybeans;oilseed rape; pulse crops; sunflower; coffee; tea; sugarcane; banana;vegetables, such as cucumbers, beans and cucurbits; tobacco; fruit andornamentals in horticulture and viticulture; turf and lawns.

The term “useful plants” is to be understood as including also (1)plants that have been rendered tolerant to herbicides like bromoxynil orclasses of herbicides as a result of conventional methods of breeding orgenetic engineering; (2) plants which have been so transformed by theuse of recombinant DNA techniques that they are capable of synthesisingone or more selectively acting toxins, such as are known, for example,from toxin-producing bacteria, especially those of the genus Bacillus;(3) plants which have been so transformed by the use of recombinant DNAtechniques that they are capable of synthesising antipathogenicsubstances having a selective action, such as, for example, theso-called “pathogenesis-related proteins”; and (4) plants which may alsocomprise one or more “output traits” (traits which provide enhancedproduct quality), such as traits which alter the fatty acid compositionof the plant/seed, for example provide altered levels of oleic acidand/or stearic acid or traits which provide industrial products such as,for example, pharmaceuticals (including antibodies) and also industrialenzymes (e.g. phytase, xylanase, glucanase).

The crystal modification B is also effective to protect naturalsubstances of plant and/or animal origin, their processed forms ortechnical material against attack of fungi.

The amount of the crystal modification B to be applied, will depend onvarious factors, such as the subject of the treatment, such as, forexample plants, soil or seeds; the type of treatment, such as, forexample spraying, dusting or seed dressing; the purpose of thetreatment, such as, for example prophylactic or therapeutic; the type offungi to be controlled or the application time.

The crystal modification B can also be used together with furtherfungicides, bactericides, herbicides, insecticides, nematicides,molluscicides or mixtures of several of those active ingredients. Thecrystal modification B may be employed in any conventional form, forexample in the form of a suspension concentrate (SC), an emulsionconcentrate (EC) or a flowable concentrate for seed treatment (FS). Whenusing the crystal modification B, it is applied to the useful plants,the locus thereof or propagation material thereof, typically as acomposition (a conventional form) as described above.

The crystal modification B is applied by treating the fungi, the usefulplants, the locus thereof or the propagation material thereof with thecrystal modification B. Crystal modification B may be applied before orafter infection of the useful plants or the propagation material thereofby the fungi. The term “locus” of a useful plant as used herein isintended to embrace the place on which the useful plants are growing,where the plant propagation materials of the useful plants are sown orwhere the plant propagation materials of the useful plants will beplaced into the soil. An example for such a locus is a field, on whichcrop plants are growing. The term “plant propagation material” isunderstood to denote generative parts of a plant, such as seeds, whichcan be used for the multiplication of the latter, and vegetativematerial, such as cuttings or tubers, for example potatoes; preferably“plant propagation material” denotes seeds.

Crystal modification B is useful for controlling the following plantdiseases on useful plants: Alternaria species in fruit and vegetables;Ascochyta species in pulse crops; Botrytis cinerea in strawberries,tomatoes, sunflower, pulse crops, vegetables and grapes, such asBotrytis cinerea on grape; Cercospora arachidicola in peanuts;Cochliobolus sativus in cereals; Colletotrichum species in pulse crops;Erysiphe species in cereals; such as Erysiphe graminis on wheat andErysiphe graminis on barley; Erysiphe cichoracearum and Sphaerothecafuliginea in cucurbits; Fusarium species in cereals and maize;Gaumannomyces graminis in cereals and lawns; Helminthosporium species inmaize, rice and potatoes; Hemileia vastatrix on coffee; Microdochiumspecies in wheat and rye; Mycosphaerella fijiensis in banana; Phakopsoraspecies in soybeans, such as Phakopsora pachyrizi in soybeans; Pucciniaspecies in cereals, broadleaf crops and perennial plants; such asPuccinia recondita on wheat, Puccinia striiformis on wheat and Pucciniarecondita on barley; Pseudocercosporelia species in cereals, such asPseudocercosporella herpotrichoides in wheat; Phragmidium mucronatum inroses; Podosphaera species in fruits; Pyrenophora species in barley,such as Pyrenophora teres on barley; Pyricularia oryzae in rice;Ramularia collo-cygni in barley; Rhizoctonia species in cotton, soybean,cereals, maize, potatoes, rice and lawns, such as Rhizoctonia solani onpotato, rice, turf and cotton; Rhynchosporium secalis on barley,Rhynchosporium secalis on rye; Sclerotinia species in lawns, lettuce,vegetables and oil seed rape, such as Sclerotinia sclerotiorum onoilseed rape and Sclerotinia homeocarpa on turf; Septoria species incereals, soybean and vegetables, such as Septoria tritici on wheat,Septoria nodorum on wheat and Septoria glycines on soybean;Sphacelotheca reilliana in maize; Tilletia species in cereals; Uncinulanecator, Guignardia bidwellii and Phomopsis viticola in vines; Urocystisocculta in rye; Uromyces species in beans; Ustilago species in cerealsand maize; Venturia species in fruits, such as Venturia inequalis onapple; Monilinia species on fruits; and/or Penicillium species on citrusand apples.

When applied to the useful plants, the crystal modification B is appliedat a rate of 5 to 2000 g a.i./ha, particularly 10 to 1000 g a.i./ha,e.g. 50, 75, 100 or 200 g a.i./ha; when applied in the form of acomposition, the application rate typically range from 20 to 4000 g oftotal composition per hectare. When used for treating seed, rates of0.001 to 50 g of the crystal modification B per kg of seed, preferablyfrom 0.01 to 10 g per kg of seed are generally sufficient.

The present invention furthermore relates to a fungicidal compositioncomprising as active ingredient crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide in afungicidally effective amount together with a suitable carrier.

These compositions of the invention may be employed in any conventionalform, for example in the form of a twin pack, a suspension concentrate(SC), a suspo-emulsion (SE), a water dispersible granule (WG), anemulsifiable granule (EG), an oil dispersion (OD), an oil miscibleflowable (OF), an ultra-low volume suspension (SU), a wettable powder(WP), a technical concentrate (TK), a dispersible concentrate (DC), apowder for dry seed treatment (DS), a flowable concentrate for seedtreatment (FS), a water dispersible powder for seed treatment (WS) orany technically feasible formulation in combination with agriculturallyacceptable adjuvants.

Such compositions may be produced in conventional manner, e.g. by mixingthe active ingredient or active ingredients with appropriate formulationinerts (diluents, solvents, fillers and optionally other formulatingingredients such as surfactants, biocides, anti-freeze, stickers,thickeners and compounds that provide adjuvancy effects). Particularlyformulations to be applied in spraying forms, such as water dispersibleconcentrates (e.g. SC, DC, SE, and the like), wettable powders andgranules, may contain surfactants such as wetting and dispersing agentsand other compounds that provide adjuvancy effects, e.g. thecondensation product of formaldehyde with naphthalene sulphonate, analkylarylsulphonate, a lignin sulphonate, a fatty alkyl sulphate, andethoxylated alkylphenol and an ethoxylated fatty alcohol. Thesecompositions may also comprise further pesticides, such as, for example,fungicides, insecticides or herbicides.

A seed dressing formulation is applied in a manner known per se to theseeds employing the compositions according to the invention and adiluent in suitable seed dressing formulation form, e.g. as an aqueoussuspension or in a dry powder form having good adherence to the seeds.Such seed dressing formulations are known in the art.

In general, the formulations include from 0.01 to 90% by weight of theactive agent, from 0 to 20% agriculturally acceptable surfactant and 10to 99.99% solid or liquid formulation inerts and adjuvant(s), the activeagent being at least the crystal modification B, and optionallycomprising other active agents. Concentrated forms of compositionsgenerally contain in between about 2 and 80%, preferably between about 5and 70% by weight of active agent. Application forms of the compositionsmay for example contain from 0.01 to 20% by weight, preferably from 0.01to 5% by weight of active agent. Whereas commercial products willpreferably be formulated as concentrates, the end user will normallyemploy diluted formulations.

The present invention furthermore relates to a method of controllingphytopathogenic diseases on useful plants or on propagation materialthereof, which comprises applying to the useful plants, the locusthereof or propagation material thereof a composition comprising asactive ingredient crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide in afungicidally effective amount together with a suitable carrier.

The preparation of modification B is carried out, for example, asdescribed in the embodiments below.

EXAMPLE P14 Preparation ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(Purity: >99%) in Modification B

240 g of crystalline 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylicacid (9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(purity: 97.6%; syn/anti ratio 94:6), prepared starting from9-isopropyl-5-amino-benzonorbornene (syn/anti ratio 90:10) as describedin example P6, was mixed with 560 g methanol at a temperature of 60° C.The mixture was heated to 65° C. and stirred until the crystallinematerial was dissolved. The solution was cooled over a time period of 20minutes to a temperature of 40° C. and then over a time period of 2hours to 25° c. During that time period a precipitate was formed. Theprecipitate was filtered at 25° C. and dried at 60° C. under vacuum. 113g of pure syn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(purity: >99%, m.p. 128° C., yield: 47%) was obtained. The crystallinematerial was analyzed by differential scanning calorimetry and x-raydiffraction and was identified as crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide nopresence of modification A was detected (see FIGS. 1, 3 and 5).

EXAMPLE A4 Preparation ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic Acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide inModification A

Crystalline syn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide(purity of syn/anti-compounds: 94.1%; syn/anti ratio 84:16) was preparedas described in example P6 starting from9-isopropyl-5-amino-benzonorbornene (syn/anti ratio 87:13). Thecrystalline material was analyzed by differential scanning calorimetry,Raman spectroscopy and x-ray diffraction and was identified as crystalmodification A of syn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylicacid (9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,no presence of modification B was detected (see FIGS. 2, 4 and 6).

FORMULATION EXAMPLES

The Examples which follow serve to illustrate the invention, “activeingredient” denoting the crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide.

Suspension concentrates active ingredient 40% propylene glycol 10%nonylphenol polyethylene glycol ether (15 mol of 6% ethylene oxide)Sodium lignosulfonate 10% carboxymethylcellulose 1% silicone oil (in theform of a 75% emulsion in water) 1% Water 32%

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired dilution can be obtained by dilution with water. Using suchdilutions, living plants as well as plant propagation material can betreated and protected against infestation by microorganisms, byspraying, pouring or immersion.

Wettable powders a) b) c) active ingredient 25%  50% 75% sodiumlignosulfonate 5%  5% — sodium lauryl sulfate 3% —  5% sodiumdiisobutylnaphthalenesulfonate —  6% 10% phenol polyethylene glycolether —  2% — (7-8 mol of ethylene oxide) highly dispersed silicic acid5% 10% 10% Kaolin 62%  27% —

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording wettablepowders that can be diluted with water to give suspensions of thedesired concentration.

Powders for dry seed treatment a) b) c) active ingredient 25% 50% 75%light mineral oil  5%  5%  5% highly dispersed silicic acid  5%  5% —Kaolin 65% 40% — Talcum — 20 

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording powders thatcan be used directly for seed treatment.

Dusts a) b) c) Active ingredient  5%  6%  4% talcum 95% — — Kaolin — 94%— mineral filler — — 96%

Ready-for-use dusts are obtained by mixing the active ingredient withthe carrier and grinding the mixture in a suitable mill. Such powderscan also be used for dry dressings for seed.

Extruder granules Active ingredient 15% sodium lignosulfonate  2%carboxymethylcellulose  1% Kaolin 82%

The active ingredient is mixed and ground with the adjuvants, and themixture is moistened with water. The mixture is extruded and then driedin a stream of air.

Coated granules Active ingredient 8% polyethylene glycol (mol. wt. 200)3% Kaolin 89% 

The finely ground active ingredient is uniformly applied, in a mixer, tothe kaolin moistened with polyethylene glycol. Non-dusty coated granulesare obtained in this manner.

Flowable concentrates for seed treatment active ingredient 40% propyleneglycol 5% copolymer butanol PO/EO 2% tristyrenephenole with 10-20 molesEO 2% 1,2-benzisothiazolin-3-one (in the form of a 20% 0.5% solution inwater) monoazo-pigment calcium salt 5% Silicone oil (in the form of a75% emulsion in water) 0.2% Water 45.3%

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired dilution can be obtained by dilution with water. Using suchdilutions, living plants as well as plant propagation material can betreated and protected against infestation by microorganisms, byspraying, pouring or immersion.

DESCRIPTION OF FIGURES

FIG. 1 shows the x-ray pattern, FIG. 3 shows the Raman spectrum and FIG.5 shows the DSC plot of crystal modification B as prepared in exampleP14.

FIG. 2 shows the x-ray pattern, FIG. 4 shows the Raman spectrum and FIG.6 shows the DSC plot of crystal modification A as prepared in exampleA4.

FIG. 7 shows the x-ray pattern of crystal modification B as prepared inexample P5.

FIG. 8 shows the x-ray pattern of crystal modification B as prepared inexample P6.

1. A process for the preparation of a compound of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, which comprises a) reacting a compoundof formula II

wherein R₁ and R₂ are as defined for formula I, with at least onereducing agent to form a compound of formula III

wherein R₁ and R₂ are as defined for formula I; and (b) reacting thatcompound with at least one reducing agent to form a compound of formulaIV

wherein R₁ and R₂ are as defined for formula I; and (c) converting thatcompound into the compound of formula I by reaction with a compound offormula V

wherein Q is chlorine, fluorine, bromine, iodine, hydroxy or C₁-C₆alkoxyand R₃ is as defined for formula I.
 2. A process according to claim 1wherein, in the compound of formula I, R₁ and R₂ are methyl and R₃ isCF₂H.
 3. A process according to claim 1 wherein, in Process Step c), thecompound of formula IV is reacted with a compound of formula V wherein Qis chlorine, fluorine or bromine and R₃ is as defined for formula I. 4.A process according to claim 1 wherein, in Process Step c), the compoundof formula IV is reacted with a compound of formula V wherein Q ischlorine, bromine, iodine or hydroxy and R₃ is as defined for formula I.5. A process according to claim 4 wherein a single reducing agent isused in Process Step a).
 6. A process according to claim 4 wherein thecompound of formula III obtained in Process Step a) is reacted to form acompound of formula IV directly, without isolation of an intermediate.7. A process according to claim 4 wherein, in Process Step c), thecompound of formula IV is reacted with a compound of formula V wherein Qis hydroxy and R₃ is as defined for formula I.
 8. A process according toclaim 4 wherein, in a compound of formula I, R₁ and R₂ are methyl and R₃is CF₂H.
 9. A process according to claim 4 wherein, in Process Step b),hydrogen in the presence of a rhodium catalyst is used as reducing agentand the compound of formula III

wherein R₁ and R₂ are as defined for formula I, is reacted to form acompound of formula IV

wherein R₁ and R₂ are as defined for formula I and wherein the ratio ofcompound of formula IVa (syn)

wherein R₁ and R₂ are as defined for formula I, to compound of formulaIVb (anti)

wherein R₁ and R₂ are as defined for formula I, is more than 90:10. 10.A compound of formula IV

wherein R₁ and R₂ are as defined for formula I in claim 1 and whereinthe ratio of compound of formula IVa (syn)

wherein R₁ and R₂ are as defined for formula I in claim 1, to compoundof formula IVb (anti)

wherein R₁ and R₂ are as defined for formula I in claim 1, is from 90:10to 99:1.
 11. (canceled)
 12. (canceled)
 13. A process for the preparationof a compound of formula IV

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, which comprises a) reacting a compound of formula II

wherein R₁ and R₂ are as defined for formula IV, with at least onereducing agent to form a compound of formula III

wherein R₁ and R₂ are as defined for formula IV; and (b) converting thatcompound with at least one reducing agent into the compound of formulaIV.
 14. A process for the preparation of a compound of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, which comprises aa) reacting6-nitro-anthranilic acid with a nitrite, selected from isoamyl nitriteand tert-butyl nitrite, and with a compound of formula C

wherein R₁ and R₂ are as defined for formula I, to form a compound offormula II

wherein R₁ and R₂ are as defined for formula I, and a) reacting thatcompound with a reducing agent to form a compound of formula III

wherein R₁ and R₂ are as defined for formula I; and (b) reacting thatcompound with a reducing agent to form a compound of formula IV

wherein R₁ and R₂ are as defined for formula I; and (c) converting thatcompound into the compound of formula I by reaction with a compound offormula V

wherein Q is chlorine, bromine, iodine or hydroxy and R₃ is as definedfor formula I.
 15. A process according to claim 14 for the preparationof a compound of formula I wherein R₁ and R₂ are methyl and R₃ is CF₂H,which comprises (aa) reacting 6-nitro-anthranilic acid with tert-butylnitrite and with a compound of formula C wherein R₁ and R₂ are methyl toform a compound of formula II wherein R₁ and R₂ are methyl; and a)reacting that compound with hydrogen in the presence of a rhodium/carboncatalyst to form a compound of formula III wherein R₁ and R₂ are methyl;and (b) reacting that compound with hydrogen in the presence of a Raneynickel catalyst to form a compound of formula IV wherein R₁ and R₂ aremethyl; and (c) converting that compound into the compound of formula Iby reaction with a compound of formula V wherein Q is hydroxy and R₃ isCF₂H, in the presence of an activating agent, the reaction being carriedout in the presence of a base.
 16. A compound of formula II

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl.
 17. (canceled)
 18. A compound of formula III

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, with the exception of9-isopropylidene-5-amino-benzonorbornene.
 19. A compound of formula IV

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl, with the exception of 9-isopropyl-5-amino-benzonorbornene.20. A compound of formula IA

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl.
 21. A compound of formula VI

wherein L is a C₁-C₆alkylene chain and R₃ is CF₃ or CF₂H.
 22. A compoundof formula VI according to claim 21 wherein L is an ethylene chain andR₃ is CF₂H.
 23. (canceled)
 24. A process for the preparation of acompound of formula I

wherein R₁ and R₂ are each independently of the other hydrogen orC₁-C₅alkyl and R₃ is CF₃ or CF₂H, which comprises a) reacting a compoundof formula II

wherein R₁ and R₂ are as defined for formula I, with a reducing agent toform a compound of formula III

wherein R₁ and R₂ are as defined for formula I; and b) reacting thatcompound with a reducing agent to form a compound of formula IV

wherein R₁ and R₂ are as defined for formula I; and d) reacting acompound of formula Va

wherein Q₁ is chlorine, fluorine, bromine, iodine or C₁-C₆alkoxy and R₃is as defined for formula I, with a compound of formula VIIHO-L-OH  (VII), wherein L is as defined for formula VI, to form acompound of formula VI

wherein L is a C₁-C₆alkylene chain and R₃ is as defined for formula I;and e) converting the compound of formula VI into the compound offormula I by reaction with the compound of formula IV.
 25. Crystalmodification B of syn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylicacid (9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide,wherein said crystal modification is characterized by an x-ray powderdiffraction pattern, expressed in terms of d-spacings and relativeintensities, wherein said an x-ray powder diffraction pattern comprisesthe following characteristic lines: 13.42 Å (strong), 9.76 Å (medium),6.93 Å (medium), 6.74 Å (medium), 4.79 Å (medium), 4.73 Å (medium), and3.66 Å (medium).
 26. The crystal modification of claim 25 furthercharacterized by having the x-ray powder diffraction pattern depicted inFIG.
 1. 27. The crystal modification of claim 25 further characterizedby having in the thermogram in differential scanning calorimetry anendothermic signal with a peak in the range from 120° C. to 128° C. 28.The crystal modification of claim 25 in substantially pure form.
 29. Acomposition for control of diseases caused by phytopathogens on usefulplants or on propagation material thereof, that, in addition tocustomary inert formulation adjuvants, comprises as active ingredient atleast crystal modification B ofsyn-3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid(9-isopropyl-1,2,3,4-tetrahydro-1,4-methano-naphthalen-5-yl)-amide in afungicidally effective amount.
 30. A method of controlling diseasescaused by phytopathogens on useful plants or on propagation materialthereof, which comprises applying to the useful plants, the locusthereof or propagation material thereof a composition according to claim29.
 31. A compound of formula IV prepared by the process of claim 13.